a. Field of Invention
This invention pertains to an adapter which may be used to connect a tubular member such as a catheter to another member in a manner which allows the tubular member to rotate around its longitudinal axis, and more particularly this invention pertains to a two-piece rotating adapter. The invention also pertains to a method of making the adapter.
b. Description of the Prior Art
In many technical fields it is desirable to have an adapter for coupling two members in such manner that they are rotatable with respect to each other around a common longitudinal axis. For example, during many surgical procedures the distal end of a catheter is inserted along a tortuous path into the body of the patient by rotating the catheter around its longitudinal axis. The catheter's proximal end is connected to a stationary device for injecting and/or withdrawing fluids through the catheter to and from the body. In such applications a rotating adapter is required for coupling these elements to permit rotation of the distal end with respect to the proximal end.
A prior art rotating adapter 10 is shown in FIG. 1. This adapter had three parts: a stem 12, having a flange 13, a collar 14 rotatably mounted on the stem 12, and an insert 16 spot-welded to the collar 14. An O-ring 18 was used to form a seal between the insert 16 and the stem 12. The manufacture of this type of adapter is expensive and very time consuming. First the collar has to be made and positioned on the stem in a first direction because its inside diameter is smaller than the stem head 20. After the collar is positioned over the stem, the insert 16 must be inserted into the collar from a second direction. The collar and insert must be mounted on the stem from opposing directions, and the completed assembly must usually be attached to a final product, e.g. a manifold, syringe, or the like.
A two-piece swivel coupling has been proposed by Waldbilig in U.S. Pat. No. 4,254,773. In this coupling, the stem is provided with a flexible lip 48 which snaps over a flange 31 of body 21. However, this device is also expensive, and difficult to assemble.